I don't understand this kind of argument at all. What does being self-aware of your own traits and interests have to do with being like everyone else? I'd argue most people have scarily little awareness of their own traits and quirks. Infinitely more unique to confidently say what you know about yourself and acknowledge there are things you don't rather than hoping your relationships to others will teach you more about yourself. They often do, sure, but one thing that makes relationships easier and more worthwhile is when the participants know who they are and can establish clear personalities and boundaries.